This invention relates to a spray nozzle apparatus for use in conjunction with paint spraying guns and the like. More particularly, the invention relates to a rotatable spray nozzle for use on airless spray guns wherein the paint or similar liquid is sprayed under high hydraulic pressures. The invention enables the spray tip to be rotatably adjusted so as to unclog particles which periodically become wedged into the very small spray orifice.
The present invention is useful for the spraying application of paints, lacquers, enamels, mastics, varnishes, and other liquid coating materials which are conveniently applied by a spraying process. The invention facilitates cleaning of the nozzle and spray passages after such spray coating operations have been completed.
This invention is an improvement over prior art apparatus designed to accomplish the same or similar purposes. For example, U.S. Pat. No. 3,116,882 issued Jan. 7, 1964, and owned by the same assignee as the present invention, discloses a turret nozzle which permits the reversal of the flow of the spray coating liquid for purposes of unclogging the spray orifice. The turret nozzle disclosed in the patent requires sealing members between the rear or inlet end of the nozzle and the housing, between the front or outlet end of the nozzle and housing, and also between the rotatable nozzle shaft and the housing. These sealing members enable the prior invention to be rotatably mounted without causing leakage of the sprayed material under the hydraulic pressures to which it is subjected. These pressures may range from 500 pounds per square inch (p.s.i.) to 2,000 p.s.i.
The prinicpal problem which must be overcome in the design of a rotatable spray nozzle, where high hydraulic pressures are encountered, is to provide an adequate sealing means which will prevent fluid leakage, even after repeated rotations of the spray nozzle and periodic instances of breaking the seal connection because of removal of the nozzle from the spray gun for cleaning, replacement, etc. The prior art solves this problem by means of providing multiple seals at all points where hydraulic pressure is or may be felt. The wearing of any of these sealing members of the prior art will cause the spray nozzle to begin leaking.